After buying God knows how many tanks, I'm thinking it's all a crap shoot. Everyone has their favorites but they work for some, not for others. My liquid supplier recommended an AeroTank and Ego Twist. I like the adjustable power capabilities and loved the tank for a couple weeks. Once the o-rings wore out and juice started leaking, I put in the other coil that came with it but it still leaked. Done everything I can think of but no success. Bought a lot of new coils but they weren't the long neck, even though the seller claimed they'd work, and had the same problem. Prior to this, I was using the vivi nova and had some success but burnt taste prompted a move. Since the aero leaked, I ordered the tank that fits all the replacement coils I bought so I'll see how that goes. Using the vivi with the twist and is a suitable guest tank until the new one arrives.
Problems I see are:
Top feed via wicks - burnt taste caused by liquid not being able to flow uphill fast enough to keep them saturated (damn gravity)
Bottom flow - as stated the piss poor o-rings supplied with the tanks go to hell in a couple weeks causing liquid to drain out and in to the inhale tube. Nothing like a mouthful of juice. I've used o-rings in industrial applications and while they may be made from different composites, two weeks is pitiful.
I have already spent a ton of cash on tanks and have my fingers crossed that some day I can find a system that is headache free but I'm not very convinced.